Five people are dead and the son of a police officer is in custody after multiple stabbings at a house party in Canada.

The stabbing happened near the University of Calgary, the police chief said, calling it the worst mass murder in Calgary's history.

Police Chief Rick Hanson said the suspect is the son of a 33-year veteran of the Calgary police force and a student at the University of Calgary.

"We have never seen five people killed at one scene," Hanson said. "The scene was horrific."

Police said the suspect was invited to the party and shortly after arriving picked up a large knife and began stabbing the victims one by one early on Tuesday morning (local time). He said about 20 people were at the party when the stabbings occurred.

Hanson said the victims ages range from 22 to 27. He said the dead were all "good kids". Neither they nor the suspect had any prior involvement with police, Hanson said. The students were celebrating the last day of classes.

The police chief said they would not release the name of the suspect until first-degree murder charges are announced later Tuesday. He said the suspect left his work at a grocery store before arriving to the party.

Three males were found dead at the home. A male and a female died at a local hospital.

Police said the suspect, in his 20s, was arrested with the help of the police canine unit about 40 minutes after the stabbings and that he was taken to hospital for treatment for dog bites.

There was no immediate word on charges or the possible motive.

Hanson said the suspect brought a weapon, but used a knife from the house. He said there's nothing to indicate the suspect was drunk or had been doing drugs.

Hanson said the father of the suspect is devastated.

Multiple witnesses were taken to the campus and are currently being interviewed by detectives, police said.

The blue-sided house where the stabbings occurred is on a quiet, tree-lined residential street. It was surrounded with yellow police tape as medical examiner staff brought three bodies out on stretchers.

Neighbour Doug Jones said about a dozen students had been drinking beer around a firepit in the backyard earlier in the night, but they weren't rowdy. They were talking about politics and the stock market. They took the party inside about 9pm and he heard nothing after that.

Other residents of the area say the house was being rented by University of Calgary students and that the party was related to the student union's annual Bermuda Shorts Day, held Monday.

Bermuda Shorts Day, shortened by students to BSD, is an annual outdoor party on campus with live music and beer gardens to celebrate the final day of classes.

The school's student newspaper, The Gauntlet, wrote about the tradition two weeks ago in a story titled: "BSD: It'll be a bloodbath."

On Twitter, many students wrote about how they started drinking early in the morning Monday and continued after the campus event at parties elsewhere.

University of Calgary President Elizabeth Cannon said they are "deeply saddened" by the news. Cannon said it was a house party off campus.